This invention relates to winged agricultural implements and, particularly, to means for controlling the range of wing motion permitted in different modes of operation.
Agricultural implements, such as a planters and tillage devices, have increased in operating width, providing winged configurations that fold into a narrow transport orientations for travel over the roadways, yet expand to operating widths of thirty to sixty feet. When these large agricultural implements are operating and come to the end of the field, i.e. the headlands, the implement must be turned around to go back the other direction in the field. At the headlands, it is desirable to raise the ground working devices to an inoperative, non-ground engaging position while making the turn, including those supported on the wings, without requiring the implement to be placed into the transport orientation.
Furthermore, such implements, particularly the tillage implements, are more effective by increasing the force exerted thereby to press the ground working devices into the ground. The actual weight of the implement itself exerts a force to urge the ground working devices into the ground; however, that force can be increased by transferring weight from the tractor through the use of a hydraulic system that works against the tractor hitch to push the implement toward the ground, thereby increasing the force exerted on the ground engaging devices.
U.S. Pat. No. 5,687,798, issued Nov. 18, 1997, to Flexi-Coil Ltd. describes a hydraulic lock mechanism for wing lift cylinders to prevent the wings from drooping when the implement middle section is raised. Co-pending U.S. patent application Ser. No. 08/891,204, corresponding to Canadian Application Serial No. 2,210,238, filed by Flexi-Coil Ltd. describes a down-force system for the tool bar of an agricultural machine including a hydraulic mechanism for maintaining a constant down-force on the rear of the tool bar during operation.